Every prose check and prose format run exits with one of the codes below, which is the contract a CI gate reads. When two outcomes apply to one run, the higher code wins. A format run that writes an auto-fix exits 0 once the rewrite is written, since the change was applied rather than left pending, whereas check on the same source exits 1.
Per-File Failures Stay Local
A parse failure in one file produces exit code 3 for that file, and every other file in the tree is still formatted or checked.
No findings, no rewrite pending.
prose check and prose format when the input already conforms.prose format also returns it for a rewrite a second run would change, because that defect belongs to the formatter rather than to the file, and the notice on stderr reports it rather than a code of its own.The usual CI job is one prose check step that fails on any non-zero exit. A project that wants to gate rewrites and lints separately can branch on 2 independently of 1, because a lint finding never auto-fixes and so never resolves on its own.
- run: uv tool install prose-formatter
- run: prose check .The GitHub Actions integration page covers the annotation and SARIF formats that show findings inline beside the gate.
When a job runs Ruff too, each tool exits with its own code from its own step, and a non-zero exit from either fails the gate with no extra wiring. The codes do not combine, so the failing step tells the developer which tool reported the finding. Under the default step order the job stops at the first non-zero step, so when both would fail, only the first shows. if: always() on the Prose step runs it regardless, so both results appear in one run.
prose check --help and prose format --help print the same table below the option list, so the codes are readable from the terminal.
The CLI Reference lists the flags that produce each code.